An infrared data communication module conforming to the IrDA is an example of optical communication module provided with a light emitting element and a light receiving element for interactive communication (See Patent Document 1, for example). Such infrared data communication modules have been widely used for a notebook computer, a cell phone and an electronic personal organizer, for example.
FIG. 28 shows an example of conventional infrared data communication module of this kind. The infrared data communication module X shown in the figure includes a light emitting element 92, a light receiving element 93 and a drive IC 94 which are mounted on a substrate 91, and a resin package 95. The resin package 95 includes two lens portions 95a and 95b positioned to face the light emitting element 92 and the light receiving element 93, respectively. The light emitting element 92 emits infrared rays. The directivity of the infrared rays emitted from the light emitting element 92 is enhanced by the lens portion 95a, and then the infrared rays exit upward in the figure. The infrared rays traveling from above is converged by the lens portion 95b onto the light receiving element 93. In this way, the infrared data communication module X performs interactive communication utilizing infrared rays.
However, the infrared data communication module X has the following drawbacks.
Recently, there is an increasing demand for the use of an infrared data communication module X for remote control of electrical appliances such as a television, in addition to the use for data communication conforming to the IrDA. In using the infrared data communication module for remote control, the distance between the infrared data communication module and the electrical appliance which is the object to be irradiated with infrared is considerably long, as compared with that in using the infrared data communication module for data communication. To cope with this condition, the amount of infrared rays emitted from the light emitting element 92 needs to be increased. One of the measures to increase the amount of infrared rays emitted from the light emitting element 92 is to increase the power supply to increase the output. Specifically, in using the infrared data communication module for data communication, current of several tens of mA is supplied to the light emitting element 92. On the other hand, to use the infrared data communication module for remote control, current of about 200 mA needs to be supplied. When such a large amount of current is supplied, a large amount of heat is produced from the light emitting element 92. Generally, however, the substrate 91 and the resin package 95 have a low thermal conductivity. Therefore, it is difficult to properly dissipate the heat produced from the light emitting element 92 to the outside of the infrared data communication module X. Therefore, the infrared data communication module X may be unduly heated to a high temperature. For this reason, it is difficult to sufficiently increase the output of the infrared data communication module X to realize the use of the module for remote control.
The size of electronic devices such as a notebook computer, a cell phone and an electronic personal organizer is being reduced year by year. Further, to improve the function of such an electronic device, the density at which electronic components are mounted to the electronic device is being increased considerably. Accordingly, there is a strong demand for the size reduction of the infrared data communication module X. To reduce the size of the infrared data communication module X, a relatively small light emitting element 92 needs to be used. To reliably perform data communication while reducing the size of the infrared data communication module X, it is necessary to increase the amount of infrared rays to be emitted from the light emitting element 92.
To form the resin package 95 by transfer molding, a mold is pressed against an aggregate board, and resin material is injected into the cavity of the mold. Then, the resin-molded body to become the resin package 95 is removed from the mold. The removal process is performed by pushing out the resin-molded body by an ejector pin provided at the mold. Generally, since a relatively large space exists between the lens portions 95a and 95b, the ejector pin is pressed to a region between the lens portions 95a and 95b. However, by this pressing, an excessively large force may be applied to the drive IC 94. In such a case, the drive IC 94 or a wire (not shown) provided for electrical connection of the drive IC 94 may be broken.
Further, the root of the lens portion 95a, 95b stands generally perpendicularly to the surface around the lens portion and is likely to be held strongly by the mold. Therefore, in removing the resin-molded body from the mold, only the lens portions 95a, 95b are sometimes kept held by the mold. When the ejector pin is pressed against the resin-molded body in this state, an excessively large stress is applied to the root of the lens portions 95a, 95b. This stress may form a crack at the root of the lens portions 95a, 95b. 
To mount the infrared data communication module X to a circuit board of a notebook computer, a cell phone or an electronic personal organizer, for example, the technique of reflow soldering is employed. In reflow soldering, solder paste is melted in the reflow furnace. The solder paste changed into liquid has surface tension. Due to the surface tension, the infrared data communication module X may unduly move.
Patent Document 1: JP-A-2003-244077